Method and apparatus for preventing unauthorized use in systems having alternative control for avoiding defect areas on recording media

ABSTRACT

A method of preventing unauthorized use includes defining a first original medium ID information stored in a predetermined order which indicates a location of the defect area of an original recording medium, when a block of data to be stored in a defect area of recording media is to be read in a system which has an alternative control for reading a block of data from an alternate area instead of the defect area without accessing the defect area. The method also includes defining a second original medium ID information as a part of data which is stored in the original recording medium and which is to be prevented against unauthorized use, reading out the first original medium ID information from the predetermined address of a recording medium to be judged for unauthorized use and reading out the second original medium ID information as a part of data from the recording medium to be judged. The final step includes judging unauthorized use of data based on the read out first original medium ID information and the read out second original medium ID information.

This is a divisional of application Ser. No. 08/406,104, filed Mar. 17,1995, now U.S. Pat. No. 5,930,825.

BACKGROUND OF THE INVENTION

This invention relates to a method of preventing unauthorized use,particularly a method of preventing unauthorized use of data or softwaresuch as programs stored on a recording medium such as an optical disk, afloppy disk or a magnetic disk.

The spread of large-capacity, portable recording media such as opticaldisks, floppy disks and magnetic disks has been accompanied by anincrease applications that deal with large quantities of digitalinformation. As a result, there has been a great increase in suchdigital information as data in image files and word-processor documents,games, word processing software and application programs for CAD or thelike.

Information recorded on a recording medium such as an optical disk isdigital information and is characterized by the fact that it can berecorded on other media without experiencing any decline in quality. Putanother way, this feature of digital information means that it can becopied with ease. A problem that arises here is that confidentialinformation as well as data and software such as application programsnot purchased legally can be used upon being copied unlawfully from theoriginal (the original recording medium). The losses sustained bysoftware developers is immeasurable. Such unlawful copying is aviolation of copyright laws and hinders the spread of such media aslarge-capacity, portable optical disks. Accordingly, an effective methodof preventing unauthorized unlawful copying is required.

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a method wherebythe illegal copying of software that has been recorded on a recordingmedium can be prevented.

A second object of the present invention is to provide a method wherebysoftware, even if it has been copied illegally, is prevented from beingused by arranging it so that the software cannot be executed.

According to the present invention, the foregoing objects are attainedby providing a method of preventing unauthorized use. The methodincludes the steps of providing a table, which stores a correspondingrelationship between physical addresses and logical addresses ofsoftware, and a security program for preventing unauthorized use of thesoftware, obtaining a corresponding relationship between physicaladdresses on a storage medium, on which the software has been stored,and logical addresses by executing the security program before thesoftware is executed, comparing this corresponding relationship with thecorresponding relationship in the table, and preventing unauthorized useof the software by disallowing execution of the software in a case whereresult of the comparison indicates that use of the software would beunauthorized or unlawful.

Further, according to the present invention, the foregoing objects areattained by providing a method of preventing unauthorized use. Themethod includes the step of adding to software a medium ID as well as asecurity program for preventing unauthorized use of the software. Italso includes constructing a system so adapted that, in an ordinarymode, a prescribed location at which the medium ID is recorded isregarded as being a defective location and an alternate areacorresponding to this defective location is accessed, while, in amaintenance mode, the prescribed location is accessed. The methodfurther includes reading data out of the prescribed location uponestablishing the maintenance mode by executing the security programbefore execution of the software, which requires comparing this datawith the medium ID that has been added on to the software, and allowingexecution of the software upon establishing the ordinary mode if thedata and the medium ID agree and disallowing execution of the softwareif the data and the medium ID fail to agree.

Furthermore, according to the present invention, the foregoing objectsare attained by providing a method of preventing unauthorized useincluding the step of recording an ID of an original at a prescribedlocation of a recording medium by irradiating the prescribed locationwith a laser beam to irreversibly deform or cause a change in theproperties of the surface of the medium. The method includesincorporating, in software, the ID, address data esignating the locationat which the ID has been recorded and a security program for preventingunauthorized use of the software. Further, the method requires readingdata from the location, which has been designated by the address data,by executing the security program before execution of the software, andcomparing the data read with the ID incorporated in the software andallowing or disallowing execution of the software based upon results ofthe comparison.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for describing the principles of the presentinvention (in a first aspect thereof);

FIG. 2 is a diagram for describing the principles of the presentinvention (in a second aspect thereof);

FIG. 3 is a perspective view showing the system configuration;

FIG. 4 is a block diagram showing the electrical construction of thesystem;

FIG. 5 is a diagram for describing the constitution of an optical disk;

FIG. 6 is a diagram for describing a partitioned structure;

FIG. 7 is a diagram for describing directory structure;

FIG. 8 is a diagram for describing file management;

FIG. 9 is a diagram showing the composition of software according to afirst embodiment of the invention;

FIGS. 10A, 10B are diagrams for describing a correspondence tableshowing the correspondence between physical and logical addresses;

FIG. 11 is a flowchart of processing for preventing unauthorizedcopying;

FIGS. 12A, 12B are diagrams for describing a physical-logical addresstable on a copied disk;

FIGS. 13A, 13B are diagrams for describing a physical-logical addresstable on an ordinary original and on a copy disk;

FIG. 14 is a diagram showing the composition of software according to asecond embodiment of the invention;

FIG. 15 is a diagram for describing a correspondence table showing thecorrespondence between physical and logical addresses in the secondembodiment;

FIGS. 16A, 16B are diagrams for describing a correspondence tableshowing the correspondence between logical and physical block addresseson the entirety of an optical disk;

FIG. 17 is a flowchart of processing for preventing unauthorized copyingaccording to a second aspect of the invention;

FIG. 18 is a correspondence table showing the correspondence betweenphysical and logical addresses on a copied disk;

FIGS. 19A, 19B are diagrams for describing a correspondence tableshowing the correspondence between physical and logical addresses tableon an ordinary original and on a copy disk;

FIG. 20 is a diagram for describing a third embodiment of the presentinvention;

FIG. 21 is a flowchart of processing for preventing unauthorized copyingaccording to a third embodiment of the present invention;

FIG. 22 is a diagram for describing a method of forming pits; and

FIG. 23 is a diagram for describing a fourth embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) Overview of the Invention

FIG. 1 is a diagram for describing an overview of a first aspect of thepresent invention. Shown in FIG. 1 are an original recording medium(also referred to as the “original”) 1 and software 100 that has beenrecorded on the original 1. The software 100 includes main software 101such as an application program, and a correspondence table 102indicating the correspondence between logical addresses and physicaladdresses. The latter, which are located on the original, store softwaredata conforming to the logical addresses. The software 100 furtherincludes a checking program 103 for preventing unlawful or unauthorizedcopying (unlawful use).

The software is written at physical addresses of the recording medium inunits of a prescribed size and the software is executed upon being readout from the physical addresses of the recording medium in the order ofthe logical addresses. The corresponding relationship 102 between thelogical addresses and the physical addresses at which the software dataconforming to these logical addresses is stored, as well as the checkingprogram 103 for preventing unauthorized use, is recorded on the original1 by being added to the main software 101. Before execution of thesoftware 100 that has been recorded on a prescribed recording medium(the original or a copy), the actual corresponding relationship betweenthe logical addresses and the physical addresses on the recording mediumat which the software data conforming to these logical addresses isstored is obtained by the checking program 103. Next, the correspondingrelationship obtained and the corresponding relationship 102 that hasbeen added to the software are compared. If the two agree, it is deemedthat the recording medium is the original and execution of the mainsoftware 101 is allowed. If the two do not agree, execution of thesoftware is not allowed. If this arrangement is adopted, thecorresponding relationship between the logical addresses and physicaladdresses in the copy is made different from the correspondingrelationship between the logical addresses and physical addresses in theoriginal, thereby blocking execution of the copied software and makingit possible to prevent unauthorized copying.

FIG. 2 is diagram for describing an overview of a second aspect of thepresent invention. Shown in FIG. 2 are an original recording medium (the“original”) 1, a normal sector 2 in which the medium ID of the originalis recorded, an alternate sector 3, software 110 that has been recordedon the original, main software 111 such as an application program, themedium ID 112 of the original and a checking program 113 for preventingunlawful use.

The medium ID is recorded in the normal sector 2 of the original 1, andthe ID 112 of the original and the checking program 113 for preventingunlawful or unauthorized use are recorded on the original 1 by beingadded to the main software 111. Control is performed in such a mannerthat, in an ordinary mode, the normal sector in which the medium ID hasbeen recorded is treated as being a defective sector and the alternatesector 3 is accessed instead of the defective sector. According tocontrol in a maintenance mode, however, the normal sector 2 is accessedrather being treated as a defective sector. When the software 110 thathas been stored on a prescribed recording medium (the original or acopy) is executed, the maintenance mode is established and the data isread out of the normal sector 2 by the checking program for preventingunlawful use, and a check is performed to determine whether this dataagrees with the medium ID of the original 1 added to the software. Ifthe two agree, the recording medium is regarded as the original, theordinary mode is established and execution of the main software 111 isallowed. If the two do not agree, then the recording medium is deemed tobe a copy and execution of the software is not allowed. If thisarrangement is adopted, the data that has been registered in thealternate sector 3 is recorded in the normal sector 2 of the copy whenthe software 110 is read from the original and copied to the copy in theordinary mode; hence, the data read out of the normal sector of the copydiffers from the medium ID of the original. As a result, execution ofthe copied software is blocked so that unlawful or unauthorized copyingcan be prevented.

(B) Embodiment

(a) System Configuration

FIG. 3 is a diagram showing the configuration of a system in which anoptical disk serves as the recording medium. The system includes anoptical disk 1, an optical disk drive 21, a host system (computer) 31, adata input unit (control panel) 41 having a keyboard 41 a and a mouse 41b, a display unit 51 such as a CRT or liquid-crystal display panel, anda printer 61. A hard disk and a floppy disk may be provided as required.

FIG. 4 is a block diagram showing the electrical construction of thesystem, in which components identical with those shown in FIG. 2 aredesignated by like reference characters. Shown in FIG. 4 are the opticaldisk drive 21, a hard disk drive 22, the host system 31, I/O controllers71 a, 71 b and an SCSI (small computer system interface) bus 72. AnSCSI, which is an interface for connecting a computer to an externalstorage device, follows the standards of the ANSI (American NationalStandard Institute). By way of example, an SCSI bus is composed of adata bus, which comprises eight bits and one parity bit, and ninecontrol buses. Such an SCSI bus is capable of having up to eight SCSIdevices (a host computer, a disk device controller, etc.) connectedthereto, and these devices possess respective identification numbers(referred to as “IDs” or “identifiers”) 0 to 7. In FIG. 4, ID0, ID1 areassigned to the I/O controllers 71 a, 71 b, respectively, and ID7 isassigned to the host system 31. The one optical disk drive 21 and theone hard disk drive 22 are connected to the I/O controllers 71 a, 71 b,respectively, but two or more of these drives can be connected to eachof these I/O controllers.

The host system 31 includes a central processing unit (processor) 31 a,a memory (main memory device) 31 b, a DMA controller 31 c, a hostadapter 31 d and I/O controllers 71 c, 71 d, these components beingconnected to a host bus 31 e. A floppy disk drive 23 is connected to theI/O controller 71 c. The control panel 41, display unit 51 and printer61 are connected to the I/O controller 71 d.

The host system 31 and the I/O controllers 71 a, 71 b are interconnectedvia SCSI interfaces, and the I/O controllers 71 a, 71 b are connected tothe respective drives 21, 22 by ESDI interfaces (enhanced small deviceinterfaces). In this system the optical disk drive 21 and the hard diskdrive 22 are separate from the host bus 31 e, the SCSI bus 72 isprovided separately from the host bus, the I/O controllers 71 a, 71 bfor the drives are connected to this SCSI bus and the drives 21, 22 arecontrolled by the I/O controllers 71 a, 71 b, respectively. Thislightens the load upon the host bus.

(b) Optical Disk

FIG. 5 is a diagram for describing the constitution of an optical diskbased upon international standards (ISO standards). Block numbers (0˜24)are shown along the horizontal direction and track numbers along thevertical direction. Tracks from a third track to track 9996 constitutean accessible area 10, which is an area that the user can access by theusual method. The accessible area 10 is provided with a user data area11 and an alternate sector area 12, in which data is stored rather thanin a defective sector. A defect management area 14 a is provided in thethree tracks on the inner side of the accessible area 10, and a defectmanagement area 14 b is provided in the three tracks on the outer sideof the accessible area 10. The defect management area 14 a is followedon its inner side by an inner control track (control zone) 15 a and thena blank area 16 a, and the defect management area, 14 b is followed onits outer side by an outer control track (control zone) 15 b and then ablank area 16 b.

The defect management areas each have a disk definition sector DDS inwhich a primary defect list PDL and a secondary defect list SDL arestored. The PDL and SDL together store information (alternate managementinformation) indicating the correspondence between defective sectors andalternate sectors. The PDL is recorded when the optical disk is shippedor when the disk is initialized as at the time of formatting, and theSDL is recorded in a case where a defective sector occurs owing todeterioration of the optical disk due to misuse by the user orcontamination of the optical by dust. The SDL is updated whenever adefective sector is produced.

The user data area 11 can be used upon being partitioned into one ormore sections. In DOS partitioning, each section is provided with a filemanagement area 13 a for storing file management information and a filearea 13 b for storing files, as shown in FIG. 6. Stored in the filemanagement area 13 a are a disk descriptor [a BPB (BIOS parameter block)table] 13 a-1 that describes information necessary for file managementwithin a section, redundant first and second file allocation tables(FATs) 13 a-2, 13 a-3, and a directory 13 a-4 that designates thestarting cluster number of each file. The disk descriptor 13 a-1describes the volume structure parameters of the disk, namely sectorsize (byte count per sector) SS, sector (block) count SC per cluster,FAT count FN (=2), entry count RDE of route directory, total sectorcount TS, sector count SF per FAT and sector count SPT per track.

Each of the FATs 13 a-2, 13 a-3 is constituted by a format identifier 13a-5 and FAT entries 13 a-6. The number of FAT entries 13 a-6 is equal tothe number of clusters in the section. The FAT entries take on values of0000, 0002˜MAX, FFF7, FFFF, respectively, in which 0000 means that thecluster is not in use. Further, 0002˜MAX mean that the cluster is inuse, with the next storage location of a file being designated by theparticular value. As shown in FIG. 7, each directory entry in thedirectory entry section 13 a-4 is composed of 32 bytes and has a space13 a-41 for a file name, a space 13 a-42 for a file name extension, aspace 13 a-43 for an attribute indication, a space 13 a-44 for areserved field, a space 13 a-45 for file modification time, a space 13a-46 for a file modification date, a space 13 a-47 for a startingcluster number of a file, and a space 13 a-48 for file length.

FIG. 8 is a diagram for describing a directory entry and FAT entryindicating the storage location of a file name “FILE”. The file “FILE”is stored at the cluster numbers 0004_(H)→0005_(H)→0006_(H)→000A_(H).The starting cluster number “0004” of the file is stored in thedirectory entry in correspondence with the file name “FILE”. Clusternumber “0005”, which indicates the next storage location of the file, isstored in the FAT entry of cluster number 0004, cluster number “0006”,which indicates the next storage location of the file, is stored in theFAT entry of cluster number 0005, cluster number “000A”, which indicatesthe final storage location of the file, is stored in the FAT entry ofcluster number 0006, and “FFFF”, which indicates the end of the file, isstored in the FAT entry of cluster number 000A.

(c) First Embodiment of Method of Preventing Unlawful or UnauthorizedUse According to the Invention

(c-1) Software Constitution

FIG. 9 is a diagram showing the composition of software for implementingthe prevention of unlawful or unauthorized use according to a firstembodiment of the invention. Illustrated in FIG. 9 are the optical disk(original) 1, the file management area 13 a, the file area 13 b, the FAT13 a-2 and the directory 13 a-4. The application program (the programname of which shall be “SAMPLE.TXT”) 100 is stored in the file area 13 band is composed of the main software 101, the correspondence table 102indicating the correspondence between logical addresses and physicaladdresses, the latter being located on the original 1 and storingsoftware data conforming to the logical addresses, and a checkingprogram 103 for preventing unauthorized use.

If it is assumed that the starting cluster (cluster 1) of theapplication program (SAMPLE.TXT) 100 is stored at cluster number 1(physical address 1) of the original 1, the second cluster (cluster 2)at cluster number 3 (physical address 3), the third cluster (cluster 3)at cluster number 2 (physical address 2), the fourth cluster (cluster 4)at cluster number 4 (physical address 4), and so on, then directoryentry information and FAT chain information shown in FIG. 10A is writtenin directory 13 a-4 and FAT 13 a-2, respectively.

The leading cluster, the second cluster, . . . the n-th cluster . . .where the application program (SAMPLE.TXT) 100 is written in and readout represent the logical addresses and are expressed as logical address1 (cluster 1), logical address 2 (cluster 2), . . . , logical address n(cluster n), . . . , respectively. Further, the cluster number 1,cluster number 2, . . . , cluster number n . . . in the optical diskrepresent the physical addresses and are expressed as physical address1, physical address 2, . . . , physical address n, . . . , respectively.When logical and physical addresses are defined in the manner set forthabove, the logical addresses stored at the physical addresses become asshown in FIG. 10B. This is the corresponding relationship between thephysical addresses and logical addresses, which is incorporated in theapplication program (SAMPLE.TXT), as shown in FIG. 9.

It should be noted that the correspondence table 102 need not hold thecorrespondence between all of the physical addresses storing thesoftware and the logical addresses. For example, it will suffice if thetable holds the correspondence between the first three of the physicaland logical addresses. In order that the corresponding relationshipbetween the physical and logical addresses in the original will notbecome a simple relationship, the application program is written at thephysical addresses discontinuously rather than continuously in such amanner that a simple rising or falling sequence is avoided.

(c-2) Processing for Preventing Unlawful or Unauthorized Use

FIG. 11 is a flowchart of processing for preventing unlawful orunauthorized use.

After the optical disk is loaded in the optical disk drive 21 (FIG. 4),“SAMPLE.TXT” is entered from the keyboard and the return key is pressed(step 201). As a result, the host system 31 acquires the applicationprogram SAMPLE.TXT in accordance with prescribed handshaking with theoptical disk drive 21 and stores the program in the memory 31 b (step202).

Next, the checking program for preventing unauthorized use incorporatedin the application program is started up (step 203) so that processingfor preventing unauthorized use is executed. Specifically, the directoryentry and FAT chain information are retrieved from the optical disk andthe location of the application program SAMPLE.TXT on the optical diskis read. At this time the data shown in FIG. 1OA is read (step 204).

Thereafter, the physical addresses of the starting cluster (logicaladdress 1), the second cluster (physical address 2) and the thirdcluster (logical address 3) are identified from the FAT chaininformation (steps 205˜207) and a correspondence table indicating thecorrespondence between the logical and physical addresses of theapplication program is created (step 208). When creation of thecorrespondence table is completed, the table is compared with thecorrespondence table of the original included in the application programSAMPLE.TXT (step 209).

Since the tables will agree if the optical disk is the original, fromthis point onward execution of the main part 101 of the applicationprogram is allowed (step 210).

On the other hand, if the created correspondence table does not agreewith the correspondence table of the original included in theapplication program SAMPLE.TXT, this means that the optical disk 1 is acopied disk. Accordingly, a warning or other message is displayed,execution of the main software 101 is forbidden (step 211) andprocessing is terminated.

The reason why the correspondence table created in the case of a copieddisk and the correspondence table of the original included in theapplication program SAMPLE.TXT fail to agree will now be described.

When the application program SAMPLE.TXT of the original is copied to acopy disk using a DOS copy command, the program is written to the copydisk in the order of the logical addresses and in the order of thephysical addresses as well.

Accordingly, if it is assumed that the application program SAMPLE.TXT iscopied from physical address 1 of the copy disk in regular order, thestarting cluster (cluster 1) of the application program SAMPLE.TXT willbe stored at physical address 1, the second cluster (cluster 2) atphysical address 2, the third cluster (cluster 3) at physical address 3,the fourth cluster (cluster 4) at physical address 4, . . . , and thedirectory entry and FAT chain information shown in FIG. 12A will writtenin directory 13 a-4 and FAT 13 a-2, respectively. When the correspondingrelationship between the physical and logical addresses is created fromthe directory entry and FAT chain information, the result is as shown inFIG. 12B. This differs from the physical—logical address table (FIG.10B) of the original.

When an original in FIG. 13A is copied to a copy disk, generally theresult is as shown in FIG. 13B. As a result, when the correspondencebetween the physical and logical addresses of the original is asfollows:

PHYSICAL ADDRESS C PHYSICAL ADDRESS (C + 1) PHYSICAL ADDRESS (C + 2)LOGICAL ADDRESS 1 LOGICAL ADDRESS 3 LOGICAL ADDRESS 2

the correspondence between the physical and logical addresses of thecopy disk is as follows:

PHYSICAL ADDRESS D PHYSICAL ADDRESS (D + 1) PHYSICAL ADDRESS (D + 2)LOGICAL ADDRESS 1 LOGICAL ADDRESS 2 LOGICAL ADDRESS 3

Thus, the physical—logical address tables of the original and copy diskdiffer in that (1) the physical addresses change from C to D and (2) therelationship between the physical addresses and logical addresses isdifferent. Hence, execution of the software on the copy disk isinhibited to prevent unlawful or unauthorized copying.

(d) Second Embodiment of Method of Preventing Unlawful or UnauthorizedCopying According to the Invention

In the first embodiment, the corresponding relationship between physicaland logical addresses is incorporated in an application program(software) in cluster units. This is because accessing is performed incluster units according to the DOS command. With an SCSI copy command,however, data can be read out of an original and recorded on a copy diskin block (sector) units. In such case the user data area of an opticaldisk is the same for both the original and copy disk and use based uponan unlawful copy can no longer be prevented as in the first embodiment.

In the second embodiment, therefore, the corresponding relationshipbetween physical and logical addresses is incorporated in theapplication program (software) in sector units and it is so arrangedthat the corresponding relationship of the original will differ fromthat of the copy disk.

(d-1) Software Constitution

FIG. 14 is a diagram showing the composition of software according tothe second embodiment. Illustrated in FIG. 14 are the optical disk(original) 1, the alternate sector area 12, the file management area 13a, the file area 13 b, the FAT 13 a-2, the directory 13 a-4 and thedefect management area 14 a. Though Sn is a normal sector, here it isregarded as being a defective sector, data to be recorded in the sectorSn is recorded in the alternate sector Sc and the correspondingrelationship between the defective sector (actually the normal sector)Sn and the alternate sector Sc is recorded in the defect management area14 a.

Numeral 100′ denotes an application program (let SAMPLE.TXT be the nameof the program) that has been recorded in the file area 13 b. Theapplication program 100′ is composed of main software 101′, acorrespondence table 102′ showing the correspondence between physicaland logical addresses on the original, and a checking program 103′ forpreventing unauthorized use. The application program 100′ is written inthe file area, which includes the defective sector (actually the normalsector) Sn, sequentially in the manner indicated by the arrows attachedto the dashed lines. Some of the software to be recorded in thedefective sector (actually the normal sector) Sn is recorded in thealternate sector Sc.

A sector (block) can be expressed by the track number and the sectorposition [written in the form “(i-th track, j-th sector)”] at this tracknumber. A (0th track, 0th sector) is adopted as the starting sector(first sector), the sectors that follow this sector are numberedconsecutively and the sectors can be expressed by these numbers. Theformer are defined as physical addresses and the latter as logicaladdresses.

When the physical and logical addresses are defined as set forth above,the correspondence between the physical addresses storing theapplication program and the logical addresses becomes as illustrated inFIG. 15 if the application program has been recorded from physicaladdress (F-1) as in FIG. 14. This correspondence becomes thecorrespondence table 102′ indicating the corresponding between thephysical and logical addresses. The table 102′ is incorporated in theapplication program (SAMPLE.TXT) 100′. It should be noted that thecorrespondence table 102′ need not hold the correspondence between allof the physical addresses at which the application program is recordedand the logical addresses. For example, it will suffice if the tableholds the correspondence between the first three of the physical andlogical addresses that include the defective sector.

(D-2) Correspondence Between Physical and Logical Addresses on EntireOptical Disk

FIGS. 16A, 16B are diagrams for describing correspondence betweenphysical and logical addresses on the entirety of an optical disk.Numeral 14 a denotes the defect management area. It is assumed thatblock addresses of the defective sector and alternate sector have beenwritten in the defective management area, as illustrated in FIG. 16A. Ifit is assumed that one track has been partitioned into 25 sectorsbetween the physical address (i-th track, j-th sector) of the normalsector and logical address A, the corresponding relationship indicatedby the following equation will hold:

A=25·i+j+1

However, the above equal will not hold with regard to a defectivesector. The sector having the physical block address (123rd track, 4thsector) from the defective management area is the defective sector.Consequently, the physical address of the defective sector cannot bemade to correspond to the logical block address 3080. Rather, thephysical block address (9990th track, 0th sector) of the alternatesector corresponds to this logical block address, with the result thatthe correspondence table indicating the correspondence between thelogical and physical block addresses becomes as shown in FIG. 16B.

There is only one defective sector in the case described above. However,a correspondence table indicating the correspondence between the logicaland physical block addresses of the entire optical disk is created inthe same manner even if there are a plurality of defective sectors.

(d-3) Control for Preventing Unlawful or Unauthorized Use in SecondAspect of the Invention

FIG. 17 is a flowchart of processing for preventing unlawful orunauthorized use according to a second aspect of the invention. Itshould be noted that the logical address 3080 (physical address: 123rdtrack, 4th sector) in the original is a normal sector but is regarded asbeing a defective sector, and the block addresses of the defectivesector and alternate sector are recorded in the defect management area14 a in advance, as shown in FIG. 16A. Further, the application programSAMPLE.TXT is recorded at logical addresses 3078˜3082. In this case, theportion of the software recorded at the logical address 3080 is notrecorded at the physical address (123rd track, 4th sector) but in thealternate sector (9990th track, 0th sector) instead. Accordingly, thecorrespondence between the physical and logical addresses of the firstthree sectors of the application program SAMPLE.TXT is as indicated inthe section enclosed by the dashed lines in FIG. 16B. Thiscorrespondence is incorporated in the application program 100′ as thecorrespondence table 102′ indicating the correspondence between thephysical and logical addresses.

After the optical disk is loaded in the optical disk drive 21 (FIG. 4),“SAMPLE.TXT” is entered from the keyboard and the return key is pressed(step 301). As a result, the host system 31 acquires the applicationprogram SAMPLE.TXT in accordance with prescribed handshaking with theoptical disk drive 21 and stores the program in the memory 31 b (step302).

Next, the checking program 103′ for preventing unauthorized use of theapplication program SAMPLE.TXT is started up (step 303) so thatprocessing for preventing unauthorized use is executed. Specifically,alternate management information (see FIG. 16A) indicating thecorrespondence between the defective sector and alternate sector isacquired from the defect management area of the optical disk and storedin the memory 31 b (step 304).

Next, the correspondence table indicating the correspondence between thelogical and physical addresses of the entire disk is created using thealternate management information (step 305). Thereafter, the logicaladdresses of the application program SAMPLE.TXT on the disk are obtainedfrom the information that has been stored in the file management area ofthe disk (step 306). For example, if the disk is managed in accordancewith MS-DOS, the logical address of each file will be clear from thedirectory entry, the sector count SC of sectors constituting the clusterand the FAT information. Accordingly, this file management informationis read and the logical addresses of the application program SAMPLE.TXTon the disk are obtained.

Next, the physical addresses corresponding to the first three logicaladdresses of the application program are found using the correspondencetable obtained at step 305, and a correspondence table indicating thecorrespondence between the physical and logical addresses is created(step 307).

When the correspondence table indicating the correspondence between thephysical and logical addresses has been created, this table is comparedwith the correspondence table of the original included in theapplication program SAMPLE.TXT (step 308).

If the optical disk is the original, the two tables will agree andtherefore execution of the main part 101′ of the application program isallowed from this point onward (step 309).

On the other hand, if the created correspondence table does not agreewith the correspondence table of the original included in theapplication program SAMPLE.TXT, this means that the optical disk is acopied disk. Accordingly, a warning or other message is displayed,execution of the main software 101′ is forbidden (step 310) andprocessing is terminated.

The reason why the correspondence table created in the case of a copieddisk and the correspondence table of the original included in theapplication program SAMPLE.TXT fail to agree will now be described.

When the application program SAMPLE.TXT of the original is copied to acopy disk in sector (block) units using an SCSI copy command, theprogram is written to the copy disk in the order of the logicaladdresses. Accordingly, if it is assumed that the application programSAMPLE.TXT is copied from logical address 3078 of the copy disk, then

(1) the starting sector is recorded at logical address 3078 (physicaladdress: 123rd track, 2nd sector);

(2) the second sector is recorded at logical address 3079 (physicaladdress: 123rd track, 3rd sector);

(3) the third sector is recorded at logical address 3080 (physicaladdress: 123rd track, 4th sector);

(4) the fourth sector is recorded at logical address 3081 (physicaladdress: 123rd track, 5th sector); and

(5) the fifth sector is recorded at logical address 3082 (physicaladdress: 123rd track, 6th sector).

Consequently, the correspondence table indicating the correspondencebetween the physical and logical addresses created from the copy diskbecomes as shown in FIG. 18; this differs from the correspondence tableof the original. It should be noted that the logical address 3080(physical address: 123rd track, 4th sector) is taken to be a normalsector on the copy disk. However, even if this is a defective sector,there is no possibility that an alternate sector the same as that of theoriginal will be assigned, and therefore the correspondence tables willdiffer. In the foregoing, it is described for the sake of conveniencethat the application program is recorded on the copy disk from a logicaladdress identical with that of the original. However, the probability ofthis occurring is very low.

When an original in FIG. 19A is copied to a copy disk, generally theresult is as shown in FIG. 19B. As a result, the correspondence betweenthe physical and logical addresses of the original is as follows:

PHYSICAL ADDRESS (F − 1) PHYSICAL ADDRESS G PHYSICAL ADDRESS (F + 1)LOGICAL ADDRESS 1 LOGICAL ADDRESS (I + 1) LOGICAL ADDRESS (I + 2)

However, the correspondence between the physical and logical addressesof the copy disk is as follows:

PHYSICAL ADDRESS K PHYSICAL ADDRESS (K + 1) PHYSICAL ADDRESS (K + 2)LOGICAL ADDRESS L LOGICAL ADDRESS (L + 1) LOGICAL ADDRESS (L + 2)

Thus, the physical—logical address tables of the original and copy diskdiffer in that (1) the physical addresses are different and (2) therelationship between the physical addresses and logical addresses isdifferent. Hence, execution of the software on the copy disk isinhibited to prevent unauthorized copying.

(e) Third Embodiment of Method of Preventing Unlawful or UnauthorizedUse According to the Invention

In the first and second embodiments, the original and copy disk aredistinguished based upon corresponding relationship between logical andphysical addresses. In the third embodiment, the original and copy diskare distinguished between using a medium ID.

(e-1) Constitution of Optical Disk and Software

FIG. 20 is a diagram for describing a third embodiment of the presentinvention.

Illustrated in FIG. 20 are the optical disk (original) 1, the user dataarea 11, the alternate sector area 12 and the defect management area 14a. Numeral 2 denotes the sector in which the medium ID is recorded. Thissector is regarded as being a normal sector in the maintenance mode anda defective sector in the ordinary mode. Numeral 3 denotes the alternatesector accessed instead of the sector 2 in the ordinary mode. Thecorresponding relationship between the defective sector (actually thenormal sector) 2 and the alternate sector 3 is recorded in the defectmanagement area 14 a. More specifically, the correspondence (alternatemanagement information) between the track number Td and sector number Sdof the defective sector 2 and the track number Ta and sector number Saof the alternate sector 3 is recorded in the defect management area 14a.

The application program (whose program name is SAMPLE.TXT) 110 iscomposed of the main software 111, the ID 112 of the original and thechecking program 113 for preventing unlawful use.

(e-2) Control for Preventing Unlawful Use in Third Embodiment of theInvention

FIG. 21 is a flowchart of processing for preventing unlawful use in thethird embodiment of the invention. It should be noted that the medium IDis recorded in the sector 2 at a prescribed physical address of theoriginal 1, and that the ID 112 of the original and the checking program113 for preventing unlawful use are recorded on the original 1 by beingadded to the application program SAMPLE.TXT. Further, the main softwareis assumed to have been encrypted.

After the optical disk is loaded in the optical disk drive 21 (FIG. 4),“SAMPLE.TXT” is entered from the keyboard and the return key is pressed.As a result, the host system 31 acquires the application programSAMPLE.TXT in accordance with prescribed handshaking with the opticaldisk drive 21 and stores the program in the memory 31 b. Next, thechecking program 113 for preventing unauthorized use is started up sothat processing for preventing unauthorized use is executed.

First, the mode is changed over to establish the maintenance mode (step401). The maintenance mode is a mode in which the normal sector 2 istreated as being a normal sector rather than a defective sector. Inother words, this is a mode in which no reference is made to thealternate management information that has been stored in the defectmanagement area 14 a.

Next, data (the medium ID in the case of the original and simple data inthe case of the copy disk) is read from the predetermined sector 2 (step402) and the mode is changed over to the ordinary mode (step 403). Thisis a mode in which the normal sector is treated as being a defectivesector. In other words, the ordinary mode is one in which the alternatemanagement information that has been stored in the defect managementarea 14 a is referred to as being effective.

Next, a check is performed to determine whether the read data agreeswith the medium ID of the original 1 included in the application programSAMPLE.TXT (step 404). If they agree, this means the optical disk thathas bee n loaded in the optical disk drive is the original. Accordingly,the encrypted application program is decoded (step 405) and execution ofthe main software 111 is performed in the ordinary mode on the basis ofthe decoded program (step 406).

On the other hand, if the read data does not agree with the medium ID ofthe original 1, this means that the optical disk 1 is a copied disk.Accordingly, a warning or other message is displayed and operation ishalted (step 407). The foregoing is a case in which the main software111 has been encrypted. However, encryption can be dispensed with andstep 405 can therefore be deleted.

In the case of the copied disk, the data read from the sector 2 is notthe medium ID for the following reason. In the ordinary mode, copying iscarried out by reading the application program SAMPLE.TXT 110 from theoriginal 1 and recording it on the copy disk. However in the ordinarymode, sector 2 in which the medium ID has been recorded is regarded asbeing a defective sector and therefore the alternate sector 3 isaccessed instead of the sector 2 and the data in the alternate sector 3is written in the sector 2 of the copy disk. Consequently, the data readout of the prescribed physical address (sector 2) of the copy diskdiffers from the medium ID of the original, execution of the copiedsoftware can be inhibited and unauthorized use thereof can be prevented.Unlawful or unauthorized use of the software is prevented, if randomdata is written in the alternate sector 3.

Further, even if copying is carried out in sector units in response toan SCSI copy command, duplication does not extend as far as thealternate management information recorded in the defect management areaor up to the contents of the defective sector. This makes it possible toprevent the use based upon unlawful or unauthorized copying.

In the embodiment set forth above, a case is described in which theinvention is applied to an optical disk. However, the invention is notlimited to optical disks but can of course be applied to other recordingmedia such as hard disks and floppy disks.

(f) Fourth Embodiment of Method of Preventing Unlawful or UnauthorizedUse According to the Invention

(f-1) Overview

In order to prevent copying using a medium ID, it is so arranged that auser absolutely cannot rewrite a medium ID recorded on an optical disk.If such an arrangement is adopted, the medium ID of the original and themedium ID of another optical disk will differ. Even if software iscopied to another optical disk, therefore, execution of this softwarecan be refused.

In order to make it impossible to rewrite a medium ID, it is necessaryto record the ID in a physically irreversible manner. To accomplishthis, first an absolute location (sector) is prepared on the opticaldisk and the medium ID is recorded at this location. The recordingmethod used is not of the magneto-optical type but entails rotating thedisk at low speed and recording the ID through a “write once” methodusing a high-power laser light beam. Since special equipment isnecessary in order to record on the film of a magneto-optical diskmedium by the “write once” technique, an ordinary user is entirelyincapable of rewriting the medium ID.

This embodiment will now be described taking a 3.5-inch magneto-opticaldisk as an example. In general, optical disk drives presently availableon the market have a disk rotating speed of 2400˜3600 rpm and arecording laser power of approximately 10 mW. The data area of amagneto-optical disk is capable of being rewritten, with data beingrecorded by a magneto-optical signal. A magneto-optical disk also has aROM area in which information such as disk control information isrecorded. The foregoing is for the case of a RAM disk, in which theentirety of the data area is rewritable. However, there are also disksin which all or part of the data area is a ROM area. (Such a disk isreferred to as a full ROM disk or partial ROM disk.)

Prescribed information is recorded in a ROM area in the form of pits,and a general user cannot write data in the ROM area. Accordingly,consideration has been given to recording the medium ID in the ROM areain the same manner that information is recorded in this area. However,such an expedient is not realistic. Specifically, since information andthe medium ID would be recorded in the ROM area in the form of pits byusing a substrate-forming die referred to as a stamper, a stamper havinga different ID would have to be prepared for each individualmagneto-optical disk in order to make the medium ID different for eachdisk.

(f-2) Method of Irreversibly Recording Medium ID

According to this embodiment of the invention, a magneto-optical diskhaving RAM and ROM portions is prepared and pits are formed in the ROMportion using a high-power laser while rotating the disk at a low speed.At this time the servo characteristics of the drive also are made tocorrespond to low-speed rotation. As for the method of pit formation, itis permissible to form holes completely through the recording film sincethe reading in of information from the ROM portion utilizes theintensity of reflected light. Further, if a pit signal is read in, it isunnecessary to form the holes completely through the recording film. Insuch case it is permissible to merely deform or alter the properties ofthe film.

FIG. 22 is a diagram for describing the method of pit formation. Broadlyspeaking, four types of pit formation can be used: (1) a hole-formingtype, (2) a phase-change type, (3) a bubble type and (4) a texture type.

In the hole-forming type, a recording film consisting of Te—C, Te—Se orthe like formed on a transparent substrate is irradiated with ahigh-power laser light beam to raise the temperature of the recordinglayer above the melting point or decomposition point thereof, therebyforming holes. If the recording film is subsequently scanned with a weaklaser light beam, reflected light does not return from the portionshaving the holes. Accordingly, signals can be reproduced from therecording film by detecting the intensity of reflected light using aphotodiode.

In the phase-change type, TeO₂ and Te are deposited on a transparentsubstrate by binary simultaneous vapor deposition or the like to form anamorphous film (recording film) of TeO_(x) (x=1.1˜1.5), the amorphousfilm is irradiated with a laser beam to elevate the film to itscrystallization temperature, and then the film is cooled gradually so asto change the laser-irradiated portions to the crystalline state. Sincethe amount of reflected laser light at crystalline portions differs fromthat at non-crystalline portions, data can be recorded only one time andthis data can be read subsequently.

In the bubble type, a macromolecular trigger layer and a platinum (Pt)recording layer are formed successively on a transparent substrate, anda bubble B is formed by irradiation with a laser beam. The reflectivityof laser light varies depending upon the absence or presence of bubbles,thereby making it possible to reproduce signals from the recording layerat a later time.

In the texture type, first the recording layer is formed to have pits inadvance and then the layer is irradiated with a laser beam to smoothenthe surface thereof, thereby making the reflectivity of the surfacebefore recording and the reflectivity of the surface after recordingdiffer. As a result, signals can be reproduced subsequently.

It will suffice to prepare a 64-bit signal as the medium ID, and onlyone sector need be provided for the medium ID.

(f-3) Construction of Fourth Embodiment

FIG. 23 is a diagram for describing the fourth embodiment of the presentinvention.

Illustrated in FIG. 23 are the magneto-optical disk (original) 1, theuser data area 11, a RAM area 11 a, a ROM area 11 b, a medium-IDrecording sector 120 recorded in the ROM area in a physicallyirreversible manner, and an application program (whose program name isSAMPLE.TXT) composed of main software 131, a medium ID 132 of theoriginal and a checking program 133 for preventing unlawful use. Thechecking program 133 includes an address 134 at which the medium ID isrecorded.

(f-4) Control for Preventing Unlawful or Unauthorized Use in FourthAspect of the Invention

After the optical disk is loaded in the optical disk drive 21 (FIG. 4),“SAMPLE.TXT” is entered from the keyboard and the return key is pressed.As a result, the host system 31 acquires the application programSAMPLE.TXT in accordance with prescribed handshaking with the opticaldisk drive 21 and stores the program in the memory 31 b. Next, thechecking program 133 for preventing unauthorized use of the applicationprogram SAMPLE.TXT is started up so that processing for preventingunauthorized use is executed.

The medium ID (the medium ID of the original in case of the original orthe medium ID of a copy disk in case of the copy disk) is read from thesector 120 designated by the medium-ID recording address 134. Next, acheck is performed to determine whether the read medium ID agrees withthe medium ID of the original included in the application programSAMPLE.TXT. If they agree, this means the optical disk that has beenloaded in the optical disk drive is the original. Accordingly, the mainsoftware 131 is executed. If the two do not agree, however, this meansthat the optical disk is the copy disk and, hence, a warning or othermessage is displayed and operation is halted.

Thus, the medium ID of an optical disk can be made to differ for eachindividual optical disk. Moreover, the medium ID is recorded in the ROMarea in a physically irreversible manner. As a result, even if a generaluser makes a copy of the disk using a personal computer or the like, theuser cannot rewrite his or her own medium ID, thus making it possible toprevent unlawful use of software.

In the foregoing, the medium ID is recorded in the ROM area of themagneto-optical disk, though it is possible to record the medium ID inthe RAM area instead. The operation involved in the RAM area is exactlythe same as that for performing recording in the ROM area. In the caseof the RAM area, however, a method of magnetically altering theproperties of the RAM area is more effective than that for formingholes. The reason for this is the possibility that holes formed in theRAM area may be detected as errors.

An example of a method of magnetically producing a change in propertyinvolves using a high-power laser light beam to irradiate anon-crystalline material (an amorphous ferrous metal or the like) formedon a substrate, thereby elevating the crystallization temperature, andsubsequently cooling the material to change the laser-irradiatedportions to the crystalline state. Thus, the crystallized portionsundergo a magnetic change in property that is irreversible.

In the case where the phase-change type or the bubble type is adoptedfor forming the pits, at the time when the medium ID is read, theregeneration mode for reading data from the optical disk is changed fromthe magneto-optical regeneration mode to the regeneration mode inconformity to the phase-change type or the bubble type. In thisregeneration mode, the decrease or increase of the quantity of thereflected light is not regarded as an error and the medium ID is read bychanging the quantity of light of a optical pick-up provided in amagneto-optical disk drive unit. Mode changing instruction informationis recorded in a predetermined area of the optical disk in advance sothat the magneto-optical disk drive unit changes the regeneration modeat the time of reading the medium ID. The structure of themagneto-optical disk drive unit is disclosed in Japanese laid-openpatent No. Tokkaihei 5-242505.

Although, the original medium ID is contained in the applicationprogram, it is possible to record it anywhere in the optical disk. Andwhen a plurality of application programs are recorded in the opticaldisk, it is possible to provide the original medium ID for eachapplication program.

Thus, in accordance with the present invention, it is arranged toadditionally provide software with the corresponding relationshipbetween physical addresses storing software data on an original andlogical addresses, and with a security program for preventing unlawfulor unauthorized use, obtain an actual corresponding relationship betweenphysical addresses and logical addresses on a storage medium on thebasis of the security program when the software is executed, comparethis corresponding relationship with the corresponding relationshipadded on to the software, allow execution of the software in a casewhere the result of the comparison indicates agreement and disallowexecution of the software in a case where the result of the comparisonindicates non-agreement. Accordingly, even if the software of theoriginal is copied unlawfully, the software cannot be executed, thusrendering the copy meaningless. This prevents unauthorized copying ofthe software.

Further, in accordance with the invention, it is so arranged that in acase where software has been copied from an original in cluster units,the correspondence between the logical and physical addresses on thecopy is different from the corresponding relationship on the original.Therefore, even if software is copied by a DOS command, the copiedsoftware cannot be executed and the unauthorized copying of software canbe prevented.

Furthermore, it is so arranged that the relationship between thephysical and logical addresses on an original will not become a simplerising or falling sequence. This means that even if the original iscopied, the correspondence between the physical and logical addresses onthe copy can be made different from the corresponding relationship onthe original.

Further, in accordance with the present invention, the correspondingrelationship between physical and logical addresses is managed in sectorunits, a prescribed normal sector on the original is regarded as being adefective sector and part of the software is recorded in a sector thatis an alternate to the defective sector. (A physical address of thealternate sector is incorporated in the corresponding relationship ofthe original.) As a result, it is so arranged that in a case wheresoftware has been copied from the original in sector units, the datathat has been recorded in the alternate sector is recorded in the normalsector of the copy and a physical address of the alternate sector is nolonger incorporated in the corresponding relationship on the copy. As aresult, the corresponding relationship on the copy becomes differentfrom the corresponding relationship on the original. Even if copying isperformed in sector units, execution of software can be prevented.

Furthermore, in accordance with the present invention, a medium ID isrecorded in a prescribed normal sector on an original, software isadditionally provided with the medium ID of the original and with asecurity program for preventing unauthorized copying, and the normalsector in which the medium ID has been recorded is construed to be adefective sector in an ordinary mode. Consequently, in a case wheresoftware is read from the original and recorded on a copy, the data thathas been recorded in the alternate sector is recorded in the normalsector of the copy, and the data in the prescribed normal sector of thecopy differs from the medium ID of the original. As a result, when thesoftware is executed, a maintenance mode is established by the securityprogram, the data is read out of the normal sector and it is judgedwhether the data agrees with the original medium ID that has been addedon to the software. If it is judged that the two agree, the ordinarymode is established and execution of the software is allowed. If the twodo not agree, then execution of the software is not allowed. Therefore,even if the software is copied unlawfully from the original to anotherdisk, the software cannot be executed and, hence, the copy is renderedmeaningless. This makes it possible to prevent unlawful copying.

Further, in accordance with the invention, the medium ID of an opticaldisk can be made different for each individual disk. Moreover, themedium ID is recorded in a physically or magnetically irreversiblemanner. As a result, even if a general user makes a copy of the diskusing a personal computer or the like, the user cannot rewrite his orher own medium ID so as to make it agree with the medium ID of theoriginal. This makes it possible to prevent unauthorized use ofsoftware.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

What is claimed is:
 1. A method of preventing unlawful use of softwarein a system which has an alternative control for reading a block of datafrom an alternate area of a recording medium instead of a defect areawithout accessing the defect area, wherein an original medium ID isrecorded beforehand at a prescribed location on an original recordingmedium on which the software has been recorded, data that has beenrecorded at the prescribed location on a recording medium is examinedwhen the software recorded on the recording medium is executed, and therecording medium is regarded as a copied medium and execution of thesoftware is disallowed if said examined data fails to agree with theoriginal medium ID, said method comprising the steps of: adding to thesoftware the original medium ID as well as a security program forpreventing unlawful use of the software; constructing the system soadapted that, in an ordinary mode, the prescribed location at which theoriginal medium ID is to be recorded is regarded as being a defectivelocation and the alternate area corresponding to said defective locationis accessed, and in a maintenance mode for examining the data that hasbeen recorded at the prescribed location, the prescribed location isregarded as being a normal location and the prescribed location isaccessed; recording beforehand data other than the original medium ID inthe alternate area of the original recording medium; when the softwareis read from the original recording medium and a copied medium iscreated by recording the software on another recording medium in saidordinary mode, recording said data that has been recorded in thealternate area of the original recording medium at the prescribedlocation of the copied medium at which the original medium ID is to berecorded whereby data read from the prescribed location of the copiedmedium is made different from said original medium ID in saidmaintenance mode; establishing the maintenance mode by executing thesecurity program before execution of the software recorded on arecording medium to be judged for unlawful use; reading data out of theprescribed location on the recording medium to be judged for unlawfuluse; comparing this data with the original medium ID that has been addedon to the software; and allowing execution of the software uponestablishing the ordinary mode if the data and the original medium IDagree, thereby the recording medium is regarded as the original mediumand disallowing execution of the software if the data and the originalmedium ID fail to agree, thereby the recording medium is regarded as acopied medium.
 2. A computer system which has an alternative control forreading a block of data from an alternate area of a recording mediuminstead of a defect area without accessing the defect area, wherein anoriginal medium ID is recorded beforehand at a prescribed location on anoriginal recording medium on which software has been recorded, data thathas been recorded at the prescribed location on a recording medium isexamined when the software recorded on the recording medium is executed,and the recording medium is regarded as a copied medium and execution ofthe software is disallowed if said examined data fails to agree with theoriginal medium ID, said system comprising: means for adding to thesoftware the original medium ID as well as a security program forpreventing unlawful use of the software; means for constructing thesystem so adapted that, in an ordinary mode, the prescribed location atwhich the original medium ID is to be recorded is regarded as being adefective location and an alternate area corresponding to this defectivelocation is accessed, and in a maintenance mode for examining the datathat has been recorded the prescribed location, the prescribed locationis regarded as being a normal location and the prescribed location isaccessed; means for recording beforehand data other than the originalmedium ID in the alternate area of the original recording medium; meansfor recording the data that has been recorded in the alternate area ofthe original recording medium at the prescribed location of a copiedmedium at which the original medium ID is to be recorded, whereby dataread from the prescribed location of the copied medium is made differentfrom the original medium ID in the maintenance mode; means forestablishing the maintenance mode by executing the security programbefore execution of the software recorded on a recording medium to bejudged for unlawful use; means for reading data out of the prescribedlocation on the recording medium; means for comparing this data with theoriginal medium ID that has been added on to the software; and means forallowing execution of the software upon establishing the ordinary modeif the data and the original medium ID agree, thereby the recordingmedium is regarded as the original medium and disallowing execution ofthe software if the data and the original medium ID fail to agree,thereby the recording medium is regarded as the copied medium.
 3. Amethod of preventing unauthorized use of software recorded on anoriginal recording medium in a system which has an alternative controlfor reading a block of data from an alternate area instead of a defectarea without accessing the defect area, comprising the steps of:recording a first original medium ID at a prescribed location on theoriginal recording medium; recording on the original recording medium,correspondence between address of said prescribed location and anaddress of an alternate location from which data other than said firstoriginal medium ID is read in an ordinary mode; adding to the software asecond original medium ID for preventing unauthorized use of thesoftware; when the software is read from the original recording mediumand copied on another recording medium in said ordinary mode, readingthe data from said alternate location of the original recording mediumand recording said data at the prescribed location of said anotherrecording medium, whereby data read from the prescribed location of thecopied medium is made different from said first original medium ID in amaintenance mode; at the time of processing for preventing unauthorizeduse of the software in said maintenance mode, reading out data from theprescribed location of a recording medium to be judged for unauthorizeduse; comparing this data with said second original medium ID that hasbeen added on to the software; and judging unauthorized use of thesoftware in accordance with the result of the comparison.
 4. A computersystem which has an alternative control for reading a block of data froman alternate area instead of a defect area without accessing the defectarea, comprising; means for recording a first original medium ID at aprescribed location on an original recording medium; means for recordingon said original recording medium, correspondence between an address ofsaid prescribed location and an address of an alternate location fromwhich data other than said original medium ID is read in an ordinarymode; means for adding to software recorded on the original recordingmedium a second original medium ID for preventing unauthorized use ofsaid software; means for reading the data from the alternate area of theoriginal recording medium and recording the data at a prescribedlocation of a copied medium, whereby data read from said prescribedlocation of said copied medium is made different from said firstoriginal medium ID in a maintenance mode; means, at the time ofprocessing for preventing unauthorized use of the software in saidmaintenance mode, for reading out data from the prescribed location of arecording medium to be judged for unauthorized use; means for comparingthis data with said second original medium ID that has been added on tothe software; and means for judging unauthorized use of the software inaccordance with the result of the comparison.
 5. A recording medium in asystem which has an alternative control for reading a block of data froman alternate location instead of a defect location without accessing thedefect location of the recording medium when a block of data stored inthe defect location is read, comprising: a first area storing data andsoftware, in which a first original medium ID is recorded at aprescribed location of the first area, and a second original medium IDfor preventing unauthorized use of said software is added to thesoftware; a second area including the alternate location; and a thirdarea storing correspondence between address of said prescribed locationand an address of the alternate location from which data other than saidoriginal medium ID is read in an ordinary mode, and wherein data is readfrom said prescribed location in a maintenance mode for examiningwhether the data agrees to the first original medium ID or not bycomparing the data and said second original medium ID.
 6. A method ofpreventing unauthorized use of information recorded on an originalrecording medium in a system which has an alternative control forreading a block of data from an alternate location instead of a defectlocation without accessing the defect location, the original recordingmedium storing an original recording medium ID in a prescribed location,special data other than the original recording medium ID in an alternatelocation and correspondence between an address of the prescribedlocation and an address of the alternate location from which the specialdata is read in an ordinary mode, said method comprising the operationof: reading the special data from the alternate location of the originalrecording medium instead of the prescribed location and recording thespecial data at the prescribed location of a copied medium, whereby dataread from the prescribed location of the copied medium is made differentfrom the original medium ID in a maintenance mode; reading out, at thetime of processing for preventing unauthorized use of the information inthe maintenance mode, data from the prescribed location of a recordingmedium to be judged for unauthorized use; comparing the data from theprescribed location of a recording medium to be judged for unauthorizeduse with the original medium ID; and judging unauthorized use of theinformation in accordance with the result of the comparison.
 7. Acomputer system which has an alternative control for reading a block ofdata from an alternate location instead of a defect location withoutaccessing the defect location in an ordinary mode, and reads and recordsdata from and to an original recording medium storing an originalrecording medium ID in a prescribed location, a special data other thanthe original recording medium ID in an alternate location andcorrespondence between an address of said prescribed location and anaddress of the alternate location from which said special data is readin an ordinary mode, said system comprising: means for reading thespecial data from the alternate location of the original recordingmedium instead of the prescribed location and recording the special dataat the prescribed location of a copied medium, whereby data read fromthe prescribed location of the copied medium is made different from theoriginal medium ID in a maintenance mode; means for reading out, at thetime of processing for preventing unauthorized use of information in themaintenance mode; data from the prescribed location of a recordingmedium to be judged for unauthorized use; means for comparing the datafrom the prescribed location of a recording medium to be judged forunauthorized use with the original medium ID; and means for judgingunauthorized use of information in accordance with the result ofcomparison.
 8. A recording medium is a system which has an alternativecontrol for reading a block of data from an alternate location insteadof a defect location without accessing the defect location of therecording medium when a block of data stored in the defect is read,comprising: a first area storing information, in which an originalmedium ID is recorded at a prescribed location of the first area forpreventing unauthorized use of the information; a second area includingan alternate location which corresponds to the prescribed location andin which a special data other than the original medium ID is recorded;and a third area storing correspondence between an address of theprescribed location and an address of the alternate location from whichthe special data is read in an ordinary mode, and wherein data is readfrom the prescribed location in a maintenance mode for examining whetherthe data agrees to the original medium ID or not by comparing the dataand the original medium ID.